Optical communication systems are desirable because of the wide bandwidths available for the information signal channels. In general, there is a direct trade off between increased bandwidth capabilities and vulnerability to large scale channel disruption by transmission medium failure. The ability of a network to be restorable is increasingly important with increasing bandwidth capability. Wavelength division multiplexed (WDM) optical networks are particularly desirable because of their restoration capabilities and suitability for minimizing the optical fiber length for the interconnection of system nodes. In order to provide restoration capabilities in the event of a fiber break a WDM ring network requires at least two parallel fibers.